Collagen is a complex structural protein which provides strength and flexibility to skin, hair and nails. Collagen is an essential and major component of muscles, tendons, cartilage, ligaments, joints and blood vessels. There are three main types of collagen: I, II and III. Types I and III are primarily found in skin, tendon and bone. In contrast, type II is found predominantly in articular cartilage. Collagen is an unusual protein, in that the proportion of glycine residues is nearly one-third which is unusually high. Proline is also present to a much greater extent in collagen than in most other proteins. Moreover, collagen contains two amino acids, 4-hydroxyproline and 5-hydroxylysine, that are found in very few other proteins. The amino acid sequence of collagen is remarkably regular, nearly every third amino acid being glycine. In addition, the sequence glycine-proline-hydroxyproline recurs frequently. In contrast, globular proteins rarely exhibit regularities in their amino acid sequences (Stryer, L., Biochemistry, Third Edition, W. H. Freeman and Co., New York, 1988, pp. 262).
In 1986, collagen was sold for the first time in the United States for use as a food supplement. Collagen (a mixture of Types I and II) was extracted from calf skin tissue, hydrolyzed and prepared in powdered form for use as a dietary supplement. The composition was sold under the name "Hydrolyzed Collagen Beauty Supplement.TM." (Smarter Nails & Hair, Inc., Newport Beach, Calif.). In 1987, "Hydrolyzed Collagen Beauty Supplement Tablet.TM." (Smarter Nails & Hair, Inc., Newport Beach, Calif.) was sold which comprised collagen powder and 10 mg vitamin C compressed into 1,000 mg tablets.
U.S. Pat. No. 4,804,745 to Koepff et al. discloses agents containing collagen peptides produced by enzymatic hydrolysis for the treatment of degenerative joint diseases. These peptides can be obtained from animal skin, animal bones and other sufficiently purified connective tissue and have average molecular weights of between 30 and 45 kilodaltons.
U.S. Pat. No. 5,399,347 to Trentham et al. and Trentham et al. (Science 261:1727-1729, 1993) disclose the effective treatment of rheumatoid arthritis (RA) with water-soluble whole chick collagen type II or biologically active peptides derived therefrom. The mechanism by which the effect is believed to occur is via oral tolerization to autoantigens.
U.S. Pat. No. 5,364,845 to Henderson discloses a therapeutic composition and method for the protection, treatment and repair of connective tissue in mammals. This composition comprises glucosamine, chondroitin sulfate and manganese ascorbate. U.S. Pat. No. 5,587,363 to Henderson discloses a therapeutic composition and method for the protection, treatment and repair of connective tissue in mammals which includes aminosugars and glycosaminoglycans.
There is a constant need for compositions capable of promoting repair of damaged connective tissue. The present invention addresses this need.